Interleaved watermarking

ABSTRACT

In one embodiment, a system includes a Headend apparatus including a watermark processor to generate secondary video streams from sections of a primary video stream, group the secondary video streams in groups of at least two secondary video streams, the secondary video streams including units of data for use in watermarking across cryptoperiods in an end-user device which selects one secondary video stream in each group for rendering as part of a composited video stream in order to embed units of data of an identification in the composited video stream, wherein in each cryptoperiod, the watermark processor is operative to generate different groups of the secondary video streams from different non-overlapping portions of the primary video stream, and an encryption processor to generate control words, encrypt each secondary video stream with a different control word, and change the control word of each secondary video stream every cryptoperiod.

RELATED APPLICATION INFORMATION

The present application claims priority from U.S. Provisional PatentApplication Ser. No. 62/317,564 of Cisco Technology, Inc. filed 3 Apr.2016.

TECHNICAL FIELD

The present disclosure generally relates to interleaved watermarking.

BACKGROUND

Interleave-based broadcast video watermarks are forensic watermarkswhose payload uniquely identifies an end-user device and/or a subscriberpotentially illegally streaming content over the internet. Thewatermarks are inserted at the broadcast headend to achieve a higherlevel of security, such that the video arrives at the end-user deviceswith the watermark signal already in the video.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be understood and appreciated more fullyfrom the following detailed description, taken in conjunction with thedrawings in which:

FIG. 1 is a view of interleaved watermarking using two secondary streamsconstructed and operative in accordance with an embodiment of thepresent disclosure;

FIG. 2 is a view of interleaved watermarking using a plurality of pairsof time staggered secondary streams constructed and operative inaccordance with an embodiment of the present disclosure;

FIG. 3 is a view of a headend system constructed and operative inaccordance with an embodiment of the present disclosure; and

FIG. 4 is a view of an end-user device constructed and operative inaccordance with an embodiment of the present disclosure.

DESCRIPTION OF EXAMPLE EMBODIMENTS Overview

There is provided in accordance with an embodiment of the presentdisclosure a broadcast Headend apparatus including a watermark processorto receive a primary video stream, and select a plurality of sections ofthe primary video stream in which to embed units of data for use inwatermarking, generate a plurality of secondary video streams from theplurality of sections of the primary video stream as input, group theplurality of secondary video streams in a plurality of groups so thateach one group of the plurality of groups includes at least twosecondary video streams from the plurality of secondary video streams,the plurality of secondary video streams including units of data for usein watermarking across a plurality of cryptoperiods in an end userdevice which selects one secondary video stream from the at least twosecondary video streams in each one group every one cryptoperiod of theplurality of cryptoperiods for rendering as part of a composited videostream in order to embed units of data of an identification in thecomposited video stream, wherein in each one cryptoperiod of theplurality of cryptoperiods the watermark processor is operative togenerate different groups of the plurality of groups of secondary videostreams from different non-overlapping portions of the primary videostream, and at least one secondary video stream of the at least twosecondary video streams in a first group of the plurality of groups isdifferent from each one of the at least two secondary video streams in asecond group of the plurality of groups, and an encryption processor togenerate a plurality of control words for each one of the plurality ofsecondary video streams, encrypt each one of the plurality of secondaryvideo streams with a different control word of the plurality of controlwords, and change the different control word of each one of theplurality of secondary video streams every one cryptoperiod of theplurality of cryptoperiods.

There is also provided in accordance with another embodiment of thepresent disclosure an end-user device, including a receiver to receive aplurality of secondary video streams generated from a plurality ofsections of a primary video stream as input, the plurality of secondaryvideo streams being grouped in a plurality of groups so that each onegroup of the plurality of groups includes at least two secondary videostreams from the plurality of secondary video streams, the plurality ofsecondary video streams including units of data for use in watermarkingacross a plurality of cryptoperiods, wherein in each one cryptoperiod ofthe plurality of cryptoperiods different groups of the plurality ofgroups of secondary video streams have been generated from differentnon-overlapping portions of the primary video stream, and at least onesecondary video stream of the at least two secondary video streams in afirst group of the plurality of groups is different from each one of theat least two secondary video streams in a second group of the pluralityof groups, a demultiplexer to select one secondary video stream from theat least two secondary video streams in each one group for rendering aspart of a composited video stream in order to embed units of data of anidentification in the composited video stream, and an decryptionprocessor to receive at least one entitlement control message for eachof a plurality of cryptoperiods, for each one cryptoperiod of theplurality of cryptoperiods, generate a control word for decrypting theselected one secondary video stream in each one group for the onecryptoperiod based on the at least one entitlement control message ofthe one cryptoperiod, and for each one cryptoperiod of the plurality ofcryptoperiods, decrypt the selected one secondary video stream in eachone group based on the control word of the selected one secondary videosteam of the one group.

Encoded Versus Encrypted

The term “encoded” is used throughout the present specification andclaims, in all of its grammatical forms, to refer to any type of datastream encoding including, for example and without limiting the scope ofthe definition, well known types of encoding such as, but not limitedto, MPEG-2 encoding, H.264 encoding, VC-1 encoding, and syntheticencodings such as Scalable Vector Graphics (SVG) and LASER (ISO/IEC14496-20), and so forth. It is appreciated that an encoded data streamgenerally requires more processing and typically more time to read thana data stream which is not encoded. Any recipient of encoded data,whether or not the recipient of the encoded data is the intendedrecipient, is, at least in potential, able to read encoded data withoutrequiring cryptanalysis. It is appreciated that encoding may beperformed in several stages and may include a number of differentprocesses, including, but not necessarily limited to: compressing thedata; transforming the data into other forms; and making the data morerobust (for instance replicating the data or using error correctionmechanisms).

The term “compressed” is used throughout the present specification andclaims, in all of its grammatical forms, to refer to any type of datastream compression. Compression is typically a part of encoding and mayinclude image compression and motion compensation. Typically,compression of data reduces the number of bits comprising the data. Inthat compression is a subset of encoding, the terms “encoded” and“compressed”, in all of their grammatical forms, are often usedinterchangeably throughout the present specification and claims.

Similarly, the terms “decoded” and “decompressed” are used throughoutthe present specification and claims, in all their grammatical forms, torefer to the reverse of “encoded” and “compressed” in all theirgrammatical forms.

The terms “scrambled” and “encrypted”, in all of their grammaticalforms, are used interchangeably throughout the present specification andclaims to refer to any appropriate scrambling and/or encryption methodsfor scrambling and/or encrypting a data stream, and/or any otherappropriate method for intending to make a data stream unintelligibleexcept to an intended recipient(s) thereof. Well known types ofscrambling or encrypting include, but are not limited to DES, 3DES, andAES. Similarly, the terms “descrambled” and “decrypted” are usedthroughout the present specification and claims, in all theirgrammatical forms, to refer to the reverse of “scrambled” and“encrypted” in all their grammatical forms.

Pursuant to the above definitions, the terms “encoded”; “compressed”;and the terms “scrambled” and “encrypted” are used to refer to differentand exclusive types of processing. Thus, a particular data stream maybe, for example:

encoded, but neither scrambled nor encrypted;

compressed, but neither scrambled nor encrypted;

scrambled or encrypted, but not encoded;

scrambled or encrypted, but not compressed;

encoded, and scrambled or encrypted; or

compressed, and scrambled or encrypted.

Likewise, the terms “decoded” and “decompressed” on the one hand, andthe terms “descrambled” and “decrypted” on the other hand, are used torefer to different and exclusive types of processing.

Definitions

A “reference frame”, as used in the specification and claims, is definedas follows. If the decoding of a first video frame is at least partiallydependent on video data of a second, now decompressed, video frame, thenthe second video frame is a reference frame of the first video frame. Inolder video encoding standards, such as MPEG-2, only one reference framewas used for P-frames and two reference frames were used for B-frames.Some modern video encoding standards, such as H.264/AVC, allow the useof multiple reference frames. This allows the video encoder to chooseamong more than one previously decoded frame on which to base eachmacroblock in the next frame. While the best frame for this purpose isusually the previous frame, the extra reference frames can improvecompression efficiency and/or video quality. Note that differentreference frames can be chosen for different macroblocks in the sameframe. The maximum number of concurrent reference frames supported byH.264 is 16. Different reference frames can be chosen for a macroblock.Another video format that supports multiple reference frames is Snow,which can handle up to eight. The Theora codec provides a limited formof multiple reference frames, allowing references to both the precedingframe and the most recent intra frame.

Detailed Description

Reference is now made to FIG. 1, which is a view of interleavedwatermarking using two secondary streams 10 constructed and operative inaccordance with an embodiment of the present disclosure.

FIG. 1 shows a primary video stream 12 encrypted with a control wordCW_(MAIN). One of the secondary streams 10, “Stream 0”, is encryptedwith a control word CW₀ and one of the secondary streams 10, “Stream 1”,is encrypted with a control word CW₁. An end-user device receiving thesecondary streams 10 and the primary video stream 12 is provided with atleast one entitlement control message (ECM) which includes informationfor generating the control words, one for decrypting the primary videostream 12 and for decrypting the secondary streams 10. The ECM(s) isgenerated at a Headend. The ECM(s) is generated so that the controlwords that can be generated from the ECM(s) by end-user device enabledecrypting the primary video stream 12 and one of the secondary streams10 which includes a unit of data (e.g., a bit) which is associated withthe end-user device (such as an ID of the end-user device or an ID of asubscriber using the end-user device). It should be noted that theECM(s) generally include(s) information for generating control words forboth of the secondary streams 10. However, a secure processor (forexample, in a smart card or in the end-user device) is operative togenerate a control word for one of the secondary streams 10. The secureprocessor is programmed with logic for deciding whether to generate CW₀or CW₁. The logic is typically based on which bit of the ID is to beembedded. The knowledge of which bit needs to be embedded may beincluded in the ECM(s) or in an index encoded in the primary videostream 12, by way of example only. The secure processor also has accessto the ID that needs to be embedded, for example, the ID may be embeddedin the secure processor. So for example, if for a current cryptoperiodthe unit of data that should be embedded in the video rendered by theend-user device is a zero, then the secure processor generates controlword CW₀ of the Stream 0, and if for the current cryptoperiod the unitof data that should be embedded in the video rendered by the end-userdevice is a one, then the secure processor generates control word CW₁ ofthe Stream 1. In each subsequent cryptoperiod, the secure processorgenerates a control word so that selection of the secondary stream 10for decrypting and rendering by the end-user device is performed basedon the data which needs to be embedded in the resulting composited videostream for rendering by the end-user device.

Therefore, to embed payloads which are unique to end-user devices, theend-user devices are provisioned with control words or keys that allowthe end-user devices to decrypt just one out of the two secondary streamversions in each cryptoperiod and perform an interleave operation byinterleaving (concatenating) different portions from the two secondarystreams 10 with the primary video stream 12. Therefore, resultingdecrypted and decoded video in each end-user device is the concatenationof the primary video stream 12 with different selections from thesecondary streams 10, with one of the secondary streams 10 beinginterleaved every cryptoperiod. The different combinations of videoversions generated by the interleave operation in the end-user devicesthen serve to uniquely identify each end-user device, as the choice ofwhich control words are produced during each cryptoperiod is determinedbased on an ID associated with each respective end-user device or asubscriber or smart card, by way of example only.

It should be noted that the interleaving of FIG. 1 is based on ‘minimalinterleave’, such that the primary video stream 12 carries most of thevideo content and only relatively short portions 14 (one or more videoframes or macroblocks or slices) of the primary video stream 12 areduplicated in the secondary streams 10, where the versions of the videoactually differ. The portions 14 of the primary video stream 12 (nowduplicated in the secondary streams 10) are not broadcast as part of theprimary video stream 12 to the end-user devices. It should be noted thatif the primary video stream 12 is not broadcast at all to the end-userdevices, multiple versions of the video may be produced by longersections of the secondary streams 10 which may be combined (interleaved)at cryptoperiod boundaries. Even when the primary video stream 12 is notbroadcast at all, the secondary streams 10 are still referred to assecondary streams 10 for the sake of simplicity.

It should be noted that using two secondary streams 10 limits the numberof data units to be embedded to one data unit every cryptoperiod.Typical durations of cryptoperiods are relatively long (8-10 seconds arequite common), and thus, the capacity of the watermark (how many payloadbits of information can be embedded per time unit) is relatively low,because of the combination of the long cryptoperiod duration and thenumber of different versions of video that can be broadcastsimultaneously, which is strongly limited by bandwidth considerations.However, a high watermark capacity is desirable not only to achieve fastdetection times, but also to allow the use of special anti-collusioncodes such as those of Boneh-Shaw, Tardos, Nuida and Furon. Theanti-collusion property comes at the expense of much longer codes, suchthat encoding the ID of one subscriber out of a million subscriberswould be a few hundred bits at least and not approximately 20 bitsexpected by information theory.

In FIG. 1, the two secondary streams 10 allow embedding 1 bit ofinformation per cryptoperiod. The secondary streams 10 may include asmany insertion points, corresponding to the portions 14 in the primaryvideo stream 12 every cryptoperiod, as necessary to make the resultingwatermark robust enough, for example, but not limited to, for errorcorrection purposes.

The number of secondary streams 10 may be increased to embed more bitsevery cryptoperiod. For example, using four secondary streams, eachstream may embed either 00, 01, 10 or 11 thereby enabling embedding 2bits every cryptoperiod. In general, using a higher number of secondarystreams 10 to embed k bits of information using 2^(k) secondary streams10 requires a bandwidth of 2(k−1) times more than is used for twosecondary streams 10. In this case as well, the secondary streams 10include as many insertion points in the primary video stream 12 everycryptoperiod as necessary to make the resulting watermark robust enough.Each end-user device still needs to produce just two control words, onefor the selected secondary stream 10 and one for the primary videostream 12.

Reference is now made to FIG. 2, which is a view of interleavedwatermarking using a plurality of pairs 16 (which may be generalized togroups) of staggered secondary streams 10 constructed and operative inaccordance with an embodiment of the present disclosure. Each pair 16 ofthe secondary streams 10 allows embedding either a zero or one, by wayof example only, in the composited interleaved video output of theend-user device. Each of the secondary streams 10 has its own uniquecontrol word, for example, stream 1 of pair 1, denoted Stream¹ ₁ has acontrol word CW¹ ₁. In each cryptoperiod, a secondary stream 10 in eachpair 16 is selected by the end-user device based on the control wordgenerated by the secure processor from the ECM(s) prepared and sent bythe headend. For each pair 16 of the secondary streams 10, the end-userdevice needs one control word every cryptoperiod. In the example of FIG.2, three pairs 16 are shown (pair 0, pair 1 and pair 2). Therefore, theend-user device generates 3 control words every cryptoperiod in additionto the control word for the primary video stream 12. All the controlwords for the cryptoperiod may be generated from one or more ECMsreceived at the beginning, or prior to the start, of the cryptoperiod.The combination of the control words therefore enables the headend toforce the end-user device to embed multiple bits every cryptoperiod. Inthe example of FIG. 2, 3 bits are embedded every cryptoperiod. FIG. 2only shows one insertion point per pair 16 every cryptoperiod. However,it will be appreciated that each cryptoperiod may include more than oneinsertion point per pair 16. It will also be appreciated that thesecondary streams 10 may be used without the primary video stream 12 asdescribed above with reference to FIG. 1.

As the insertion points (corresponding to the portions 14) of the pairs16 are staggered over the cryptoperiod, (thereby effectivelysub-partitioning the cryptoperiod into “watermarking periods” which areshorter than the cryptoperiod), the bandwidth requirement of thesecondary streams 10 of FIG. 2 is the same as in FIG. 1. In FIG. 2, thenumber of bits embedded is 3 times that of FIG. 1 without addingbandwidth overhead. In general, to embed k bits of information, k pairs16 of the secondary streams 10 are used and k+1 control words aregenerated by each end-user device every cryptoperiod, k control wordsfor the secondary streams 10 and one control word for the primary videostream 12.

It will be appreciated that any suitable number of pairs 16 may be used,thereby enabling a large number of bits to be embedded everycryptoperiod. The number of pairs 16 may be limited by the availableinsertion points in a cryptoperiod as well as hardware and/or softwarelimitations for producing enough control words, for example, but notlimited to, smart card limitations and/or data limitations in ECMs etc.It will also be appreciated that each pair 16 may be a group includingmore than two secondary streams 10. For example, using four secondarystreams 10 per group could enable embedding two bits every watermarkperiod, e.g., 00 or 01 or 10 or 11.

Seamless interleaving of the secondary streams 10 and the primary videostream 12 may be implemented. One option is to provide the insertionpoints at reference frames (e.g., I-frames) and duplicate the I-framesremoved from the primary video stream 12 in the secondary streams 10with appropriate changes for the embedding. Another option may be toremove a whole group of pictures (from and inclusive of an independentlycoded reference frame until just before the next independently codedreference frame) in the primary video stream 12 for duplication in thesecondary streams 10.

Reference is now made to FIG. 3, which is a view of a broadcast headendsystem 18 constructed and operative in accordance with an embodiment ofthe present disclosure. The headend 18 includes a watermark processor34, one or more encoders 20, an ECM generation processor 22, anencryption processor 24, a multiplexer 26, a timing processor 28 andtransmission equipment 30. The elements 34, 20, 22, 24, 26, 28, 30 maybe combined together in any suitable combination implemented as one ormore processors.

The encoders 20 are operative to receive and encode a primary videostream 12 (FIG. 2). The watermark processor 34 is operative to: receivethe primary video stream 12; and select a plurality of sections of theprimary video stream 12 (corresponding to portions 14 (FIG. 2)) in whichto embed units of data for use in watermarking. The primary video stream12 may either be received by the watermark processor 34 in an encodedstate or a non-encoded state depending on the method used for embeddingdata in the secondary video streams 10 (FIG. 2). The watermark processor34 is also operative to generate secondary video streams 10 (FIG. 2)from the sections of the primary video stream 12 as input. The secondaryvideo steams 10 are grouped in a plurality of groups so that each groupincludes at least two secondary video streams 10. The secondary videostreams 10 including units of data for use in watermarking across aplurality of cryptoperiods in an end user device which selects onesecondary video stream 10 from the at least two secondary video streams10 in each group every cryptoperiod for rendering as part of acomposited video stream in order to embed units of data of anidentification in the composited video stream. In each cryptoperiod, thewatermark processor is operative to generate different groups of thesecondary video streams 10 from different non-overlapping portions 14 ofthe primary video stream 12. In each cryptoperiod, each secondary videostream 10 in one group is different from each secondary video stream 10in another group. The duplicated portions may be one or more frames,slices or macroblocks. By way of example only, in each group a firstvideo stream of the secondary video streams 10 in that group includes afirst unit of data and a second video stream of the secondary videostreams 10 in that group includes a second unit of data different fromthe first unit of data. The watermark processor 34 may be operative tovideo encode the secondary video streams 10 if the secondary videostreams 10 need video encoding.

The encryption processor 24 is operative to: generate a plurality ofcontrol words for each of the secondary video streams 10 (FIG. 2) andthe primary video stream 12; encrypt each of the secondary video streams10 (FIG. 2) with a different control word (so in each cryptoperiod eachsecondary video stream 10 is encrypted with a different control word);and encrypt the primary video stream 12 with its control word. Theencryption processor 24 is operative to change the different controlword of each secondary video stream 10 (FIG. 2) and the control word ofthe primary video steam every cryptoperiod.

The ECM generation processor 22 is operative to generate one or moreentitlement control messages for each cryptoperiod. The entitlementcontrol message(s) for each cryptoperiod include(s) information toenable the end-user devices to generate a control word for decryptingthe secondary video stream 10 (FIG. 2) selected from each group in thatcryptoperiod and one for the primary video stream 12 (FIG. 2) for thatcryptoperiod. It should be noted that the ECM(s) generally include(s)information for generating control words for all the secondary streams10 in a cryptoperiod. The different control words enable decryption ofone secondary video stream 10 (FIG. 2) per group of the secondary videostreams 10. The selected video streams when included in a compositevideo stream embed consecutive units of data of an identificationassociated with the end-user device, or a subscriber, or smart card,etc.

The timing processor 28 is operative to arrange the timing of thesecondary video streams 10 (FIG. 2) in each cryptoperiod so thatportions of the selected video streams 10 including the consecutiveunits of data are synchronized with watermarking gaps (the portions 14(FIG. 2)) in the primary video stream 12. The timing processor 28typically manages the synchronization by buffering the secondary videostreams 10 with respect to the primary video stream 12.

The multiplexer 26 is operative to multiplex the secondary video streams10 (FIG. 2) in a transport stream with the primary video stream 12. Thetransmission equipment 30 is operative to transmit the transport stream.As described above the primary video stream 12 may be omitted from thetransport stream by ensuring that the secondary video streams 10 coverall parts of the primary video stream 12.

Reference is now made to FIG. 4, which is a view of an end-user device38 constructed and operative in accordance with an embodiment of thepresent disclosure. The end-user device 38 includes a receiver 40, ademultiplexer 42, a decryption processor 44 and a decoder 46.

The receiver 40 is operative to receive a transport stream 48 includingthe secondary video streams 10 (FIG. 2) (generated from a primary videostream) and the primary video stream 12 (FIG. 3). The secondary videostreams 10 (FIG. 2) are generated as groups of video streams asdescribed above with reference to FIG. 3.

The demultiplexer 42 is operative to demultiplex the secondary videostreams 10 (FIG. 2) and the primary video stream 12 in the transportstream 48. The demultiplexer 42 is operative to select one secondaryvideo stream 10 from the secondary video streams 10 in each group ofsecondary video streams for rendering as part of a composited videostream in order to embed units of data of an identification in thecomposited video stream.

The decryption processor 44 is operative to: receive one or more ECMseach cryptoperiod; and, for each cryptoperiod, generate differentcontrol word(s) for decrypting the selected secondary video stream 10(FIG. 2) in each group and the primary video stream 12 (FIG. 3) for thatcryptoperiod based on the ECM(s) of that cryptoperiod. It should benoted that the ECM(s) generally include(s) information for generatingcontrol words for all of the secondary streams 10. However, a secureprocessor (for example, in a smart card 50 or in the end-user device 38)is operative to generate one control word for each group (e.g., pair) ofthe secondary streams 10. The secure processor is programmed with thelogic for deciding which control words to generate. The logic istypically based on which bit of the ID needs to be embeddedcorresponding to each secondary stream group. The knowledge of which bitneeds to be embedded for each group may be included in the ECM(s) or inan index encoded in the primary video stream 12, by way of example only.The secure processor also has access to the ID that needs to beembedded, for example, the ID may be embedded in the secure processor.The decryption processor 44 is operative to: for each cryptoperiod,decrypt the selected secondary video stream 10 (FIG. 2) in each groupbased on the different control word(s); and for each cryptoperiod,decrypt the primary video stream 12 based on its control word. Theselected video streams when included in a composite video stream embedat least two consecutive units of data of an identification associatedwith the end-user device 38 or subscriber or the smart card 50, in eachrespective cryptoperiod.

The decoder 46 is operative to decode the decrypted primary video stream12 and the decrypted selected secondary video stream 10 of each group asa composited interleaved video stream.

In practice, some or all of these functions may be combined in a singlephysical component or, alternatively, implemented using multiplephysical components. These physical components may comprise hard-wiredor programmable devices, or a combination of the two. In someembodiments, at least some of the functions of the processing circuitrymay be carried out by a programmable processor under the control ofsuitable software. This software may be downloaded to a device inelectronic form, over a network, for example. Alternatively oradditionally, the software may be stored in tangible, non-transitorycomputer-readable storage media, such as optical, magnetic, orelectronic memory.

It is appreciated that software components may, if desired, beimplemented in ROM (read only memory) form. The software components may,generally, be implemented in hardware, if desired, using conventionaltechniques. It is further appreciated that the software components maybe instantiated, for example: as a computer program product or on atangible medium. In some cases, it may be possible to instantiate thesoftware components as a signal interpretable by an appropriatecomputer, although such an instantiation may be excluded in certainembodiments of the present disclosure.

It will be appreciated that various features of the disclosure whichare, for clarity, described in the contexts of separate embodiments mayalso be provided in combination in a single embodiment. Conversely,various features of the disclosure which are, for brevity, described inthe context of a single embodiment may also be provided separately or inany suitable sub-combination.

It will be appreciated by persons skilled in the art that the presentdisclosure is not limited by what has been particularly shown anddescribed hereinabove. Rather the scope of the disclosure is defined bythe appended claims and equivalents thereof.

What is claimed is:
 1. A Headend apparatus comprising: a watermarkprocessor to: receive a primary video stream; and select a plurality ofsections of the primary video stream in which to embed units of data foruse in watermarking; generate a plurality of secondary video streamsfrom the plurality of sections of the primary video stream as input;group the plurality of secondary video streams in a plurality of groupsso that each one group of the plurality of groups includes at least twosecondary video streams from the plurality of secondary video streams,the plurality of secondary video streams including the units of data foruse in watermarking across a plurality of cryptoperiods in an end userdevice which selects one secondary video stream from the at least twosecondary video streams in each one group every one cryptoperiod of theplurality of cryptoperiods for rendering as part of a composited videostream in order to embed the units of data of an identification in thecomposited video stream, wherein in each one cryptoperiod of theplurality of cryptoperiods the watermark processor is operative togenerate different groups of the plurality of groups of secondary videostreams from different non-overlapping portions of the primary videostream and wherein in each one cryptoperiod of the plurality ofcryptoperiods at least one secondary video stream of the at least twosecondary video streams in a first group of the plurality of groups isdifferent from each one of the at least two secondary video streams in asecond group of the plurality of groups; an encryption processor to:generate a plurality of control words for each one of the plurality ofsecondary video streams; encrypt each one of the plurality of secondaryvideo streams with a different control word of the plurality of controlwords; change the different control word of each one of the plurality ofsecondary video streams every one cryptoperiod of the plurality ofcryptoperiods; generate a control word for the primary video stream;encrypt the primary stream with the control word of the primary videostream; and change the control word of the primary video stream everyone cryptoperiod of the plurality of cryptoperiods; and a timingprocessor to arrange a timing of the plurality of secondary videostreams in each of the plurality of cryptoperiods so that portions ofthe plurality of secondary video streams including the units of data aresynchronized with a plurality of watermarking gaps in the primary videostream.
 2. The apparatus according to claim 1, wherein each one of theat least two secondary video streams in a first group of the pluralityof groups is different from each one of the at least two secondary videostreams in a second group of the plurality of groups.
 3. The apparatusaccording to claim 1, further comprising an entitlement control messagegeneration processor to generate at least one entitlement controlmessage for each of the plurality of cryptoperiods, the at least oneentitlement control message for each one cryptoperiod includinginformation to enable the end-user device to generate a control word forthe one cryptoperiod for decrypting the one secondary video stream ineach one group.
 4. The apparatus according to claim 1, furthercomprising a multiplexer to multiplex the plurality of secondary videostreams in a transport stream.
 5. The apparatus according to claim 1,wherein a first video stream of the plurality of secondary video streamsin one group of the plurality of groups includes a first unit of dataand a second video stream of the plurality of secondary video streams inthe one group of the plurality of groups includes a second unit of datadifferent from the first unit of data.
 6. The apparatus according toclaim 1, wherein in each one cryptoperiod of the plurality ofcryptoperiods each one of the plurality of secondary video streams isencrypted with a different control word.
 7. An end-user device,comprising: a receiver to receive a primary video stream and a pluralityof secondary video streams generated from a plurality of sections of theprimary video stream, the plurality of secondary video streams beinggrouped in a plurality of groups so that each one group of the pluralityof groups includes at least two secondary video streams from theplurality of secondary video streams, the plurality of secondary videostreams including units of data for use in watermarking across aplurality of cryptoperiods, wherein in each one cryptoperiod of theplurality of cryptoperiods different groups of the plurality of groupsof secondary video streams have been generated from differentnon-overlapping portions of the primary video stream and wherein in eachone cryptoperiod of the plurality of cryptoperiods at least onesecondary video stream of the at least two secondary video streams in afirst group of the plurality of groups is different from each one of theat least two secondary video streams in a second group of the pluralityof groups; a demultiplexer to select one secondary video stream from theat least two secondary video streams in each one group for rendering aspart of a composited video stream in order to embed the units of data ofan identification in the composited video stream; and a decryptionprocessor to: receive at least one entitlement control message for eachof the plurality of cryptoperiods; for each one cryptoperiod of theplurality of cryptoperiods, generate a control word for decrypting theselected one secondary video stream in each one group for the onecryptoperiod based on the at least one entitlement control message ofthe one cryptoperiod; for each one cryptoperiod of the plurality ofcryptoperiods, decrypt the selected one secondary video stream in eachone group based on the control word of the selected one secondary videosteam of the one group; for each one cryptoperiod of the plurality ofcryptoperiods, generate a control word for the primary video stream forthe one cryptoperiod based on the at least one entitlement controlmessage of the one cryptoperiod; and for each one cryptoperiod of theplurality of cryptoperiods, decrypt the primary video stream based onthe control word of the primary video stream; and wherein portions ofthe plurality of secondary video streams including the units of data aresynchronized with a plurality of watermarking gaps in the primary videostream.
 8. The device according to claim 7, wherein each one of the atleast two secondary video streams in a first group of the plurality ofgroups is different from each one of the at least two secondary videostreams in a second group of the plurality of groups.
 9. The deviceaccording to claim 7, further comprising a decoder to decode theselected one secondary video stream in each one group for rendering aspart of the composited video stream embedding the units of data of theidentification in the composited video stream.
 10. The device accordingto claim 7, wherein a first video stream of the plurality of secondaryvideo streams in one group of the plurality of groups includes a firstunit of data and a second video stream of the plurality of secondaryvideo streams in the one group of the plurality of groups includes asecond unit of data different from the first unit of data.
 11. A methodcomprising: receiving a primary video stream; selecting a plurality ofsections of the primary video stream in which to embed units of data foruse in watermarking; generating a plurality of secondary video streamsfrom the plurality of sections of the primary video stream as input;grouping the plurality of secondary video streams in a plurality ofgroups so that each one group of the plurality of groups includes atleast two secondary video streams from the plurality of secondary videostreams, the plurality of secondary video streams including the units ofdata for use in watermarking across a plurality of cryptoperiods in anend user device which selects one secondary video stream from the atleast two secondary video streams in each one group every onecryptoperiod of the plurality of cryptoperiods for rendering as part ofa composited video stream in order to embed the units of data of anidentification in the composited video stream, wherein in each onecryptoperiod of the plurality of cryptoperiods different groups of theplurality of groups of secondary video streams are generated fromdifferent non-overlapping portions of the primary video stream andwherein in each one cryptoperiod of the plurality of cryptoperiods atleast one secondary video stream of the at least two secondary videostreams in a first group of the plurality of groups is different fromeach one of the at least two secondary video streams in a second groupof the plurality of groups; generating a plurality of control words foreach one of the plurality of secondary video streams; encrypting eachone of the plurality of secondary video streams with a different controlword of the plurality of control words; changing the different controlword of each one of the plurality of secondary video streams every onecryptoperiod of the plurality of cryptoperiods generating a control wordfor the primary video stream; encrypting the primary stream with thecontrol word of the primary video stream; changing the control word ofthe primary video stream every one cryptoperiod of the plurality ofcryptoperiods; and arranging a timing of the plurality of secondaryvideo streams in each of the plurality of cryptoperiods so that portionsof the plurality of secondary video streams including the units of dataare synchronized with a plurality of watermarking gaps in the primaryvideo stream.
 12. The method according to claim 11, wherein each one ofthe at least two secondary video streams in a first group of theplurality of groups is different from each one of the at least twosecondary video streams in a second group of the plurality of groups.13. The method according to claim 11, further comprising generating atleast one entitlement control message for each of the plurality ofcryptoperiods, the at least one entitlement control message for each onecryptoperiod including information to enable the end-user device togenerate a control word for the one cryptoperiod for decrypting the onesecondary video stream in each one group.
 14. The method according toclaim 11, further multiplexing the plurality of secondary video streamsin a transport stream.
 15. The method according to claim 11, wherein afirst video stream of the plurality of secondary video streams in onegroup of the plurality of groups includes a first unit of data and asecond video stream of the plurality of secondary video streams in theone group of the plurality of groups includes a second unit of datadifferent from the first unit of data.
 16. The method according to claim11, wherein in each one cryptoperiod of the plurality of cryptoperiodseach one of the plurality of secondary video streams is encrypted with adifferent control word.